This invention relates generally to combustors and more particularly, to methods and apparatus to facilitate decreasing combustor acoustics.
During the combustion of natural gas, pollutants such as, but not limited to, carbon monoxide (“CO”), unburned hydrocarbons (“UHC”), and nitrogen oxides (“NOx”) may be formed and emitted into an ambient atmosphere. At least some known emission sources include devices such as, but not limited to, gas turbine engines and other combustion systems. Because of stringent emission control standards, it is desirable to control emissions of such pollutants by attempting to suppress the formation of such emissions.
At least some known combustion systems implement combustion modification control technologies such as, but not limited to, Dry-Low-Emissions (“DLE”) combustors and other lean pre-mixed combustors to facilitate reducing emissions of pollutants from the combustion system by using pre-mixed fuel injection. For example, at least some known DLE combustors attempt to reduce the formation of pollutants by lowering a combustor flame temperature using lean fuel-air mixtures and/or pre-mixed combustion. However, at least some known DLE combustors experience combustion acoustics, or combustion instabilities, that can limit the overall operability and performance of a combustion system including a known DLE combustor. Over time, the magnitude of the combustion instabilities may increase to a level that may cause damage to the combustion system. As a result, operability, emissions, maintenance cost, and useful life of combustor components may be negatively affected.